HMI evolution provides a gateway to productivity
Conventionally, a human-machine interface (HMI) is viewed as a simple device which allows user inputs to be translated into signals for machines that, in turn, send information to the user. Today’s HMIs can be much more than this and are no longer simply display devices with fancy graphics. Now, HMIs can display all the real-time information needed to control a system and also can carry out monitoring operations for the machine. An HMI accesses data from multiple sources and reaches out to remote spaces, giving operators instant access to operations from anywhere.
HMIs act as the primary gateway to an automation system and directly reference tags and alarms in the controller, alerting users to a current or potential issue.
The overall benefit of using an HMI as an automation gateway is the reduced time taken in three critical areas, such as commissioning, production, and maintenance. These, in turn, arise through three key characteristics of the HMI: remote connectivity, easy interaction, and advanced troubleshooting.
Advanced remote connectivity
By being able to interface with standard control networks (Ethernet, RS-232, and RS-422/485) and providing options for other networks (such as CC-Link, CC-Link IE, and Melsecnet/H), it is possible to monitor devices remotely, yielding reductions in maintenance times and minimizing lost production time.
Fast, convenient integration into control and automation networks enables the HMI to control and monitor other devices, such as programmable logic controllers (PLCs), servo drives, frequency inverters and robots. An HMI can interface directly to databases in a manufacturing execution system (MES), effectively acting as a communication hub within a factory-wide automation system.
Advanced functions may enable an HMI to be operated remotely on a client-server architecture with a one-to-one connection. The exclusive control of operating authority prevents operational errors that may be caused by simultaneous operation; in addition, setting passwords prevents illegal viewing or operation.
Mobile HMI software can provide a flexible option for remote control and viewing of HMIs. It allows up to five devices to be connected to an HMI, so users can connect via an Apple iPad, a Microsoft Windows phone, and a laptop PC at the same time, for example. It also allows the user to look at different screens than the ones being displayed on the HMI. In addition, it does not lock out the operator from using the HMI during remote viewing.
Easy HMI interactions
During setup and maintenance, HMIs can monitor and modify sequence programs and parameters, removing the need for an external programming device or changing cable connections. Such a feature enables users to connect a PC to the HMI and link through it transparently to connected automation equipment. Using the HMI as a gateway simplifies setup, programming, monitoring, modification and testing of components which might be mounted deep within a panel or machine.
A major contributor to reducing production downtime comes from advanced troubleshooting features, which are designed to identify and help quickly eliminate faults.
Debugging functions within the HMI avoid the need to use an external PC to commission and fault find. Even whole user manuals now can be stored on an HMI for direct access in the field. This is more convenient and can help increase plant up-time by allowing for more efficient on-site support.
More HMI functions
Data logging enables users to uniformly manage data from a number of factory automation devices connected to an HMI for later analysis. With backup and restore functions, the parameters and programs of connected equipment, such as PLCs and inverters, can be stored on the HMI. Then, if a problem arises on a piece of equipment or a new component needs to be installed, the program or parameters can be quickly restored without the need to connect a PC, minimizing downtime.
An HMI display can show alarms and if a network outage occurs, alarms are buffered in the controller. A memory card slot can allow a user to save large volumes of data, including alarms and logging data. In addition, image recording, image playback, video image input, and RGB output are available.
It is easy to see how HMIs have transformed into an effective gateway device; by offering remote control for automation systems, extended interaction with other factory automation equipment and advanced troubleshooting. These features can help save time in commissioning and maintenance of automation equipment, while increasing productivity and efficiency for users. Benefits include less downtime and increased profitability.
André Hartkopf is product manager visualization at Mitsubishi Electric Europe B.V. This appeared on the Control Engineering Europe site on Dec. 6, 2016, and was edited for the Control Engineering international page by Mark T. Hoske, content manager, CFE Media, Control Engineering, firstname.lastname@example.org.
- Human-machine interfaces serve as a hub to multiple devices and systems.
- Advanced HMI features allow secure remote connection.
- HMIs help with alarms and troubleshooting.
How could features available in new HMIs increase your productivity?
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